In the process of manufacturing a thin film transistor liquid crystal display panel, a display panel motherboard is firstly obtained by bonding an array substrate motherboard comprising a plurality of sub array substrates and a color filter substrate motherboard comprising a plurality of sub color filter substrates, then the bonded display panel motherboard is cut and divided into a plurality of display panels.
In a manufacture process of the array substrate motherboard, source and drain electrodes and an active layer of a thin film transistor are generally formed by using a dual-tone mask. That is, a source-drain electrode metal film and an active layer film are exposed by using the dual-tone mask, then the source and drain electrodes and the active layer are formed after two wet etching processes and two dry etching processes; in this way, costs are greatly saved.
After the formation of the source and drain electrodes and the active layer is completed, if any defects are found in the source and drain electrodes or the active layer in a later test process (for example, a data line connected with the source electrode is disconnected or a connection between the drain electrode and the active layer is poor, etc.), it is required to strip off the source-drain electrode metal film and re-fabricate the source and drain electrodes, that is, to re-perform the processes of forming the source-drain electrode metal film, exposing, developing and etching the source-drain electrode metal film. The process of re-fabricating the source and drain electrodes is called as a rework process. If the source and drain electrodes need to be re-fabricated, the source and drain electrodes to be re-fabricated must be precisely aligned with the previously fabricated active layer so as to ensure that the performance of the resultant transistor is normal.
At present, in order to achieve precise alignment of the source and drain electrodes with the active layer in the rework process of reforming the source and drain electrodes, a mask for forming the source and drain electrodes should be aligned with an alignment mark formed in a gate electrode metal layer. However, only aligning the mask for forming the source and drain electrodes with the alignment mark in the gate electrode metal layer cannot achieve the precise alignment between the source and drain electrodes and the active layer, and misalignment between the source and drain electrodes and the active layer often causes abnormal operations of the thin film transistor, and even leads to failure of the whole batch of products.